In industrial and medical researches as well as in many manufacturing processes for different products, some health-hazardous particles will be produced to exist in the working environment. Therefore, persons engaging in such researches or product manufacture must wear a protection suit in the working environment to isolate the particle from the wearers, and particularly to prevent the particles from entering the wearers' bodies via respiration.
After a wearer has put on the protection suit, air must be immediately supplied into the protection suit, so that there is sufficient oxygen-containing air in the protection suit for the wearer to breathe in. Therefore, it is an important and basic requirement that air can be quickly supplied into the protection suit. Generally, a protection suit is internally provided with a duct for guiding air to four limbs of the protection suit. The duct consists of an upper and a lower plastic sheet that are adhered to each other along their two lateral edges, so that a normally flat duct is formed. When the protection suit is stored in an environment with relatively high temperature and humidity, the upper and lower sheets of the duct will very possibly become attached to each other to result in a blocked duct, which no doubt seriously adversely affects the important operation of quickly supplying air into the protection suit.
Meanwhile, to protect the wearer against the health-hazardous instantaneous high pressure in the protection suit caused by movements of the wearer during work, check valves are provided on the protection suit so that the air that causes the instantaneous high pressure can be discharged from the protection suit via the check valves.